And the US officially uses SI/Metric anyhow. We just use Imperial measure as well. And those units are still understood and used by people in Canada and the UK -- probably other places as well. The little stripes that tell how tall someone is when walking out of a bank or convenience store in Canada measure in feet and inches, not centimeters. At the folk level, these are the units that have been used for a whole lot longer than meters, and will continue to be understood by anybody who has ever read a book/song/poem/play/film that talked about miles, gallons, quarts, cups, pounds, etc. Those references happen with surprising frequency, and I've not seen a Canadian (in particular) ever ask for help converting a reference from those units because they didn't get the reference. And do you ever hear the cry in a pub in London for someone to come over and have 500 ml, or are the offered a pint?
I like SI/Metric, and am relatively conversant in it. It's great for technical uses for all of the reasons everybody has already mentioned. Base 10 measures are great in a base 10 number system. But base 2 measures aren't that hard to deal with, either. 8 oz in a cup, 2 cups in a pint, 2 pints in a quart, 4 quarts in a gallon -- not that hard. Pretty life-sized stuff, really.